The invention relates to a wooden rail for a ride, particularly for a roller coaster, as well as to a method for fabricating and mounting such a wooden rail.
As explained in the book xe2x80x9cVolksbelustigungenxe2x80x9d, written by Florian Dering, Greno Verlagsgesellschaft, Nxc3x6rdlingen, 1986, pp. 119-127, the first up-and-down rides, particularly roller coasters, were mere wooden constructions. Only the wheels and the chassis of the wagons and the elevator means were made of iron. The frame was made of spruce and pine wood, and the rails were made of multiple-bonded spruce wood, with the track surface being made of maple. The rims on both edges of the rail, which served to guide, i.e. the so-called xe2x80x9cbandsxe2x80x9d (In German xe2x80x9cBandenxe2x80x9d), consisted of bonded planks and were bent in drying stoves to the desired shape of the rails.
However, due to the relatively slow driving speeds, the wooden rails at that time did not have lateral inclination, i.e. the planks were arranged in layers one over the other horizontally and parallel.
Over the course of time, these early wooden constructions were replaced by up-and-down rides or roller coasters made of steel, and in 1964 the Schwarzkopf Company of Munsterhausen/Swabian built the first roller coaster in the Federal Republic of Germany which was completely made of steel. The track constructions were of modular design and prefabricated, and were only put together to form the skeleton at the place of use, as can be deduced, for example, from DE-OS 17 03 917.
Today, most up-and-down rides or roller coasters are equipped with steel rails; in recent times, however, there is an increase in the number of wooden roller coasters with wooden rails being constructed. In addition, there are still some designs of wooden roller coasters and up-and-down rides having wooden rails, which, due to wear and tear, have to be replaced every four to seven years.
Wooden rails used for roller coasters or for general up-and-down rides are fabricated at the place where the up-and-down ride is to be erected, made of individual wooden layers, i.e. of planks, such as sawn timber at least 8 mm thick and less than 40 mm thick, or of boards, i.e. sawn timber at least 40 mm thick (see DIN 68 252). These two terms will be used interchangeably in the following description as the selection of a specific type of sawn timber depends on conditions which are of no further interest here.
The first plank/board is placed as the first layer onto the rail support provided at the trestle of the rail frame and vertically pre-bent, i.e. in vertical direction to the rail plane; a valley of the rail thus being pushed downwards or a hill of the rail being pushed upwards. Then, the second plank/board layer is placed onto the first layer in an offset manner, and both layers are then nailed together. Then, the third layer is placed, and so on, until the desired thickness is obtained.
Generally, wooden rails for roller coasters comprise approximately eight layers, although more or less layers can also be used.
Subsequently, rail connectors made of squared timber, extending at a right angle to the direction of the rails, are fixed to the prefabricated package of layers by means of screw bolts. These rail connectors function to maintain the track width of the two rails running parallel to one other; to distribute the loads from the guide wheels of the vehicle, running on the rails, to both rails; to stabilize the rails; and, if desired, to provide a catwalk for the service staff.
Afterwards, steel sheets for the running wheels and for the guide wheels of the vehicle are continuously fixed to the rail by means of screw bolts. Steel sheets for the counter wheels are also arranged at those points where the counter wheels engage.
Owing to the usual speeds encountered nowadays, each roller coaster rail, i.e. each wooden rail, is three-dimensionally curved in large regions, i.e. there are radii vertical to the rail plane and radii horizontal to the rail plane, and the lateral inclination xcex2 of the rail may constantly change. This means that the right and the left rail of a pair of rails may be inherently twisted.
In the case of rails having horizontal radii in the rail plane, the two planks/boards at which the counter wheels may engage, are often placed differently than in the case of rails without horizontal radii.
Because the planks/boards run linearly, the rail package, comprising rails with horizontal radii, is constructed in oversize segments, and the radii on the inner side of the right and left rails are worked out by carpenters, i.e. usually by hand. This is arduous, awkward, and troublesome work, as the rails are assembled manually in situ after the trestles have been placed, and the carpenters are exposed to the wind and weather.
Owing to the carpenter""s manual fabrication, the carpenters have many possibilities to deviate from the rail design. Consequently, the rails have large tolerances; in particular for the inner dimension of the rail between the steel sheets for the guide wheels and between the two rail supports from trestle to trestle. These tolerances result in rather rough rides being associated with wooden rides as compared to rides, for example, on roller coasters constructed of prefabricated steel rails.
Due to the layer-wise nailing and the subsequent bolting, the rails have only partial joint coverage and the individual layers at the joints between two subsequently following rails have no additional joint coverage, leading to the following disadvantage. While the vehicle runs past, the individual layers of planks/boards are subjected to relative displacements, which lead to loosening of nails and the formation of gaps between the individual layers, as the planks/boards are still inherently twisted. Accordingly, water may penetrate the rail causing early rotting of the wood. Furthermore, in winter the effects of frost, snow and condensation water also come into play.
The rails are deflected to a higher degree, as the individual layers are only mounted in partial composite. As there is only minor load distribution of the pressures from the running wheels over the relatively thin steel sheet, the uppermost layer is often subjected to pressure, perpendicular to the direction of the wood fiber, exceeding the admissible pressure load.
Experience shows that, owing to the above influences, wooden rails for up-and-down rides/roller coasters have to be completely replaced after a period of four to seven years.
It is an object of the invention to provide a wooden rail for an up-and-down ride, especially a roller coaster, which obviates the above-mentioned disadvantages. In particular, the wooden rail can be prefabricated industrially to the greatest possible extent, and then only needs to be mounted on the trestles.
This object is solved by the features set forth in claim 1 of the invention. Pertinent embodiments are defined by the appertaining sub-claims.
The advantages obtained by this aspect of the invention are based on construction of a rail from laminated wood board, laminated veneer wood or presspahn wood (particle board) in a wood glue construction method, wherein the board layers are arranged parallel to the rail plane, perpendicular to the rail plane, or, in a mixed construction partially parallel and partially perpendicular to the rail plane, and then are bonded, in particular glued, to each other. The rails, milled to the precise form, only need to be secured to the rail support on the trestle.
It is even possible to prefabricate pairs of rails including rail connectors and to transport them to the place where the ride is to be erected. For transport reasons, however, it is generally more advisable to only fabricate the individual rails, and to assemble them to pairs of rails at the site.
Such rails can be prefabricated at a precise accuracy of xc2x11 mm, which had not been possible heretofore, as they had to be made manually of individual layers by the carpenters at site. Thus, the quality of a roller coaster ride, employing such wooden rails, has been significantly improved.
Prefabrication of rails also reduces the time required for construction. In addition, such prefabrication is independent of the trestles, their mounting and of the current conditions prevailing at the site.
Prefabricated rails are stiffer (for the same cross section) than wooden rails produced by nailing, with the result that they deflect less; and fewer rail connectors, or absolutely none, are required. Alternatively, the rail cross section of a bonded, prefabricated wooden rail may be made smaller than that of a wooden rail produced by nailing together individual layers.
Due to its smooth surface, a bonded, prefabricated wooden rail looks better than a rail produced by nailing.
The package of prefabricated, bonded wood layers prevents any relative displacement of the individual layers of planks/boards towards each other, so that the load distribution can be defined precisely and does not change in the course of operation. Furthermore, the outer surfaces of this package are smooth and can be sealed without any problem, so that water cannot penetrate through open layers. Compared to nailed rails, the service life can thus at least be doubled, sometimes even tripled, which results in the valuable material xe2x80x9cwoodxe2x80x9d being saved, and, simultaneously, in considerable cost savings.
Generally, the board layers are arranged parallel to the rail plane and then bonded with each other, as by gluing. It is, however, also possible to arrange the individual board layers perpendicular to the rail plane or mixed, i.e. partially perpendicular and partially parallel to the rail plane, e.g., alternating, and then bond them with each other.
For special applications, for example if special features are required for the outer surface of the wooden rail, layers of oversized rough wood bonded together and milled to the precise rail form can be regarded as a kind of core for a rail, acting as the gauge for any further side or cover layers that will be bonded to said core. The desired features may then be set, for example, by selection of appropriate types of wood for the side or cover layers, but also by the appropriate processing of such layers.
The service life is also additionally prolonged by applying a wood preservative to the individual layers before or after bonding, and/or to the milled and bonded layers.
It is advisable that a plank/board of hardwood be used for the uppermost layer to improve the pressure absorption perpendicular to the wood fiber at those places where the greatest wheel pressure occurs. Alternatively, for instance, the plank/board for the uppermost layer may be hardened by silicification. Both measures, which may also be used together under extreme conditions, result in a longer service life.
The fundamental difference between prior art wooden rails and the wooden rails according to the invention becomes evident in the following comparison: fabrication and mounting of wooden rails conventionally fabricated by carpenters for a standard roller coaster requires about 6 t of nails, to be worked with manually at site, whereas fabrication and mounting of the rails according to the invention makes nails superfluous.
According to another aspect of the invention, the drawbacks of the above-mentioned nail-method, used to fabricate wooden rails for rides, are avoided. In particular, it is intended to obtain an industrial fabrication, which avoids the drawbacks arising from the carpenter""s work with wood packages at site.
This is achieved by the features of claim 7 according to the invention. Suitable embodiments are defined by the appertaining sub-claims.
Owing to the advantages obtained by this aspect of the invention, fabrication is simplified irrespective of the conditions prevailing at the place where the roller coaster is to be erected, the fabrication time for the wooden rails is shortened, and, finally, the accuracy of fabrication is increased to an extent that cannot be attained by carpenter""s work.
According to a third aspect of the invention, a method for mounting a wooden rail for a ride is provided, which obviates the disadvantages of mounting performed rails by carpenters, hitherto usual, and which, in particular, considerably reduces the mounting time at site, i.e. at the place where the ride is to be erected.
This is realized by the features of claim 13.
The advantages obtained by this aspect of the invention are based on the fact that the prefabricated rails, already completely prepared for mounting, i.e. rails, which in a preferred case are already provided with steel rails, joint areas and rail connectors, are transported to the construction site, where they are mounted to the support base, which is generally done by screw-fastening. This results in a considerable reduction of the required mounting time at site and, thus, in the influences caused by wind and weather. Furthermore, owing to the prepared rail joints, the individual rails can be connected with each other much easier, faster and also more precisely.